Let-off mechanism



June 24, 1941. w. H. BAHAN LET-'OFF MECHANISM Filed May 13, 1940 mm m mv 311ventor; WILL/HM H. BHHHN (IttornegS Patented June 24, 1941 UNITED STATES PATENT OFFICE 2,246,656 LET-ore mo A William H. Bahan, Greenville, S. 0.

Application May 13,1940, Serial N 0. 334,921

Claims. (01. 139-1100) This invention relates to a let-oii mechanism for looms which is employed for maintaining a uniform tension in the warp prior to the same being woven into cloth. It is a well known fact that great diificulty has been encountered in maintaining uniform warp tension dueto the fact that the diameter of th wound material upon the warp beam. gradually diminishes as the warp is used. As the diameter decreases, there is a necessity for a corresponding decrease in the restraining meansfor the beams; otherwise the tension of the warp will increase as the diameter of the material on the warp beam decreases.

It is an object of this invention to provide a mechanism for decreasing the restraining influence upon the beam in direct proportion to the decrease of the diameter of the material wound thereon. Specifically, I have employed a rotatable element for resisting the let-off of the warp beam, the rotation of which is adapted to be resisted by a loose weighted material. Means are provided for varying the amount of the material in which this element is adapted to rotate so that the proper amount of resistance will be oifered to the let-off of the beam regardless of the diameter of the material from thereon.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawing, in Which-- Figure 1 is an elevation showing certain portions thereof in section, illustrating my improved let-off mechanism, associated with a loom;

Figure 2 is a vertical sectional View taken along the line 2--2 in Figure 1;

Figure 3 is a sectional view similar to thelower central portion of Figure 1, illustratingthe action of loose weighted material as it resists the let-off of the warp beam.

Referring more specifically to the drawing, the numeral [0 designates a loom frame having a warp beam II with a warp material l2 wound thereon. This warp material I2 is drawn from the beam in a sheet form designated by the reference character l3, which warp passes upwardly over roller l4 and then through conventional stop motion drop wires 15. After passing through these wires, the warp I3 is divided into sheds, namely, 13a and [31), each shed passing through a suitable harness heddle l6. In the drawing, one harness heddle is shown in raised position and the other in a lowered position. The sheds Ho and B?) then pass through a conventional reed lla of loom lay l1 and is formed into cloth IS in a conventional manner due to the reciprocatory motion of a shuttle i8 which places the filling between the sheds. The cloth [9 passes over rollers 26 and 2| and then is wound upon the cloth take-up beam 22.

The parts thus far described are conventional in association with most looms which are emplayed for weaving cloth. The head of the warp beam II has integral therewith a gear 23. This gear is adapted to mesh with a pinion 24 on shaft 25, said shaft being rotatably mounted in a hearing 26 secured to framework it (Figure 2). The other end of the shaft 25 has a hub member 28 fixedly secured thereon, which hu'b member has radially extending vanes or paddles 29. The hub and the vanes 29 are encased in a suitable housing 21. It will be noted by referring toFigures 1 and 3 that the extremities of the vanes 29 are adapted. to scrape or come into close contact with the interior periphery of the housing for the major portion of the circumference. Also the sides of the vanes are adapted to move in close proximity with the interior sidewalls of the housing. A portion of the interior periphery of the housing however, extends away from the path normally travelled by the ends of the vanes 29, thereby forming a cavity or recess 35, adjacent to the upwardly moving vanes. Within the housing 21 a suitable loose weighted matter 30 such as shot or steel balls is adapted to be placed. As the cloth is Woven the warp beam l I and gear 23 are rotated in a clockwise manner due to the pull of the warp, thereby rotating the pinion 24, shaft 25, and .paddles or vanes 29 in a counter-clockwise manner. Since the lower portion of the casing or housing 21 is filled with loose weighted matter such as steel balls 36 it is evident that a resistance to the travel of the vanes will be offered. In other words, the resistance to the let-oil of the beam is oiiered by virtue of the weight of steel balls 30 resting upon the vanes a the vanes move from lowermost to uppermost position. When the vanes approach their uppermost position, the balls supported thereby will fall by gravity downwardly over the hub portion 28 and through openings 29a and 291) which are disposed between the hub and the interior of the. housing. The vanes, upon their downward travel, have none or almost only a relatively small amount of weighted matter resting thereon, because the balls will fall downwardly through opening 29w and 29b to the lower portion of the housing, and get in front of th lower vanes.

.As heretofore stated, it is desirable to decrease the resistance oifered to the turning of the warp beam as the diameter of the material ii! on the beam decreases. The proper reduction of the resisting force will maintain an even tension in the warp l3. In order to provide this means for varying the resistance oifered to the turning of the warp beam, a lever 38 has been fixedly secured to a shaft 39, the upper end of said lever being adapted to contact at all times, the periphery of the wound material [2 upon the beam H. The shaft 39 to which lever 38 is attached, is rotatably mounted in a bracket 49, which, in turn, is supported by the framework It of the loom. The other end of the shaft 39 has fixedly secured thereon, a lever 4| and the free end of this lever has pivoted thereto as at 42 a vertically disposed link 43. The upper end of the link 43 is pivoted as at 44 to the face of the housing 21. As the diameter of the material I2 decreases, it is seen by referring to Figure 1 that the upper end of lever 38 will move toward the axis of rotation of the beam, thereby rotating the lever 4| and shaft 39 in a counterclockwise manner and at the same time rotating the housing 2'! in a clockwise manner to the dotted line position indicated by reference character 211). This position of the housing will place more of the eccentric recess 35 out of the line of travel of the vanes 27 as they move upwardly: consequently a less amount of weighted material will be disposed above these vanes, resulting in a corresponding decrease in the amount of resisting force offered to the turning of beam I I.

On the other hand, if the beam H is filled with material [2 and it is necessary to create a greater resisting force in order to maintain a uniform tension in the warp l3, the housing 21 will be rotated to the dotted line position 21a. This position will be occupied by the housing, because the upper end of the lever 38 will rest a farther distance from the axis of rotation of the warp beam H. When the recess 35 of the casing 2! is disposed more directly above the upwardly travelling vanes 29, there is a greater amount of material pressing downwardly against the vanes, thereby offering a greater resistance to the turning of the vanes and also to the turning of the warp beam II.

When it is desired to vary the initial position of the housing 27, it is only necessary to remove the bolt 42 and insert it into other coinciding holes 45 and 46 in levers 4| and 43 respectively.

In order to provide ready access to the interior of the housing 21, a door 49 is pivoted as at 49 to the upper side thereof.

It is therefore seen that I have provided a means for maintaining a uniform tension in the warp as it is let ofi from a warp beam, regardless of the diameter of the material on the beam.

In the drawing and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the appended claims.

I claim:

1. In a warp tensioning device for looms, a

warp beam, a shaft driven by said beam, a plurality of radially disposed vanes extending from said shaft, and being adapted to have loose weighted matter to resist rotation, and a housing separate from the vanes and encasing said vanes and said weighted matter, and means for adjusting theposition of the housing relative to the vanes and said shaft.

2. In a warp tensioning device for looms, a warp beam, a shaft driven by said beam, a plurality of radially disposed vanes extending from said shaft, and being adapted to have loose weighted matter to resist rotation, a housing encasing said vanes for containing said weighted matter, and means adjusting the position of the housing relative to the vanes for varying the resistance offered by the loose weighted matter to the rotation of the vanes.

3. In a warp tensioning device for looms, a warp beam, a plurality of radially disposed carriers, a relatively stationary housing encasing the carriers and being adapted to support weighted loose matter, means driven by the warp beam for rotating the carriers to lift the weighted mat ter as some of the carriers move upwardly, and for releasing the material as the material approaches the top of the casing, and means for ad-- justing the position of the housing relative to the vanes to thereby regulate the amount of resistance offered by the weighted matter to the rotation of the vanes.

4. In a warp tensioning device for looms, a warp beam, a shaft driven by said beam, a plurality of radially disposed vanes extending from said shaft, and being adapted to have loose weighted matter to resist rotation, a housing encasing said vanes in said weighted matter, said housing having an eccentrically disposed cavity adjacent said vanes as they travel upwardly, means for allowing a portion of said matter carried by the upwardly moving vanes to move into said cavity and for allowing the remainder as it approaches the top to fall on the downwardly moving vanes, and means for rotating said cavity relative to said vanes to thereby vary the amount of matter engaged by the vanes and to vary the amount of matter forced into the cavity.

5. In a warp tensioning device for looms, a warp beam, a shaft driven by said beam, a plurality of radially disposed vanes extending from said shaft, and being adapted to have loose weighted matter to resist rotation, a housing encasing said vanes and said weighted matter, said housing having an eccentrically disposed cavity adjacent said vanes as they travel upwardly, and

means for allowing a portion of said matter carried by the upwardly moving vanes to move into said cavity for allowing the remainder as it approaches the top to fall on the downwardly moving vanes, and means engaging the warp on the warp beam for automatically controlling the position of the housing relative to the vanes to thereby control the elevation of said cavity to vary the amount of weighted matter engaged by the vanes.

WILLIAM H. BAHAN. 

